APPLICATION OF ALTIMETER EXPERIMENTS OF PLANET-B ORBITER TO THE EXPLORATION OF MARTIAN SURFACE AND SUBSURFACE LAYERS

Application of altimeter experiment of Planet-B orbiter to the explora tion of Martian surface and subsurface layers is planned by using the ALT mode data from the ''PWS (Plasma Waves and Sounder)'' instrument. The topographic profile along-the-track from the orbiter to the nadir point of Martian surface can be obtained in detail owing to the high a ccuracy of the PWS altimetry of about 20 m. The characteristics of alt imeter echo intensities are also applicable to obtain the electromagne tic properties which were functions of bulk density, humidity, and abu ndance of ferromagnetic minerals of the uppermost layer of Martian sur faces. The surface macroscopic roughness was also studied since the ri se time was slower for the echo from the rougher surface. Another poss ibility of the application of the altimeter experiment can be given by identifying the subsurface echoes and it is used as a probe for sensi ng physical properties from tens to hundreds meters below the surface, including possible exploration of liquid water.